Gas manifolds having multiple valves for directing different gases to various destinations are widely used in analytical instrumentation, specialty gas blending, microelectronic component manufacture, and selected process industries. In some applications, gas manifold systems are highly automated and are operated by sophisticated computer control systems. In other applications, because of cost, safety, and/or reliability considerations, some or all of the valves in a gas manifold system are designed for manual or hand operation. In the manual operation of these manifolds, an operator must set the position of a plurality of valves correctly so that various gases flow to the proper end user, analytical instrument, or apparatus. Processes using these hand-operated manifolds typically are batch processes requiring a number of cyclically repeated steps, each of which requires a different set of manifold valve positions. Because operator error in some of these systems can cause significant economic losses and may result in serious safety hazards, careful attention to valve positions during critical operating steps is extremely important.
Various types of valve position indicators for gas manifold valves are widely available and usually indicate whether a valve is open or closed. Many of these are integrated with electric or pneumatic drive mechanisms and display the valve position by means of electrical or mechanical readout mechanisms which are integral parts of the valves.
In certain applications in which an operator requires valve position information for manual manifold valves, it is desirable to have simple valve position indicators that are not electrically or mechanically driven. It is also desirable to have valve position indicators that can be easily installed on and removed from standard valves not originally designed or manufactured with position indicators. The present invention, which is described below and defined by the claims that follow, provides a simple valve position indicator that can be attached to standard valves to serve as visual operator reminders of required valve positions. The invention also includes the use of multiple valve position indicators installed on a manifold system to remind operators of a plurality of required valve settings, in both open and closed positions, for critical process steps in multiple-step manufacturing operations.
The invention includes a detachable valve position indicator comprising an elongate tab having a first end and a second end, a first flexible member having a first and a second end, a second flexible member having a first and a second end, wherein the first end of the first flexible member and the first end of the second flexible member are attached to the first end of the elongate tab, a first connecting means attached to the second end of the first flexible member, and a second connecting means attached to the second end of the second flexible member. The first and second flexible members can be placed around a valve body, the first connecting means can be engaged with the second connecting means to attach the elongate tab to the valve body, and the first connecting means can be disengaged from the second connecting means to remove the elongate tab from the valve body.
The first and second flexible members may have a semicircular shape and may be generally coplanar with the elongate tab. The first and second connecting means may comprise opposing ratchet-toothed connection members each having ratchet teeth of opposite pitch angles which can be engaged by sliding the connection members circumferentially about the valve body, thereby attaching the elongate tab to the valve body, and which can be disengaged by sliding the ratchet teeth apart in directions perpendicular to the plane formed by the first and second flexible members and the elongate tab, thereby removing the elongate tab from the valve body.
The elongate tab typically has a first surface and a second surface, and one of the surfaces may include an area having a different color than the color of the first and second flexible members and the color of the first and second connecting means. The detachable valve position indicator may be made of material selected from the group consisting of a polymeric material, a metallic material, and combinations thereof.
The invention also includes a valve assembly comprising a valve base, a valve bonnet attached thereto, a rotatable valve stem extending coaxially through the valve bonnet, a rotatable valve handle attached to the valve stem and having a plane of rotation which is generally perpendicular to the axis of the valve stem, and an indicator tab attached to the valve base or the valve bonnet and extending outward from the valve body or valve bonnet in a direction generally parallel to the plane of rotation of the valve handle. The rotatable valve handle can be disposed in at least a first position and a second position, wherein the rotatable handle when disposed in the first position may render the indicator tab invisible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle, and wherein the rotatable handle when disposed in the second position may render the indicator tab visible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle.
The rotatable valve handle when disposed in the first position may allow the flow of a fluid through the valve base and when disposed in the second position may prohibit the flow of a fluid through the valve base. Alternatively, the rotatable valve handle when disposed in the first position may prohibit the flow of a fluid through the valve base and when disposed in the second position may allow the flow of a fluid through the valve base. The valve assembly may be characterized by a valve type selected from the group consisting of a ball valve, a butterfly valve, and a diaphragm valve. The first position and the second position of the rotatable valve handle may define a one-quarter turn of the valve stem.
In another embodiment, the invention is a method for determining a desired position of a handle of a valve comprising
(a) providing a valve assembly comprising a valve base, a valve bonnet attached thereto, a rotatable valve stem extending coaxially through the valve bonnet, a rotatable valve handle attached to the valve stem and having a plane of rotation which is generally perpendicular to the axis of the valve stem, and a moveable indicator tab attached to the valve base or the valve bonnet and extending outward from the valve body or valve bonnet in a direction generally parallel to the plane of rotation of the valve handle, wherein the rotatable valve handle can be disposed in at least a desired first position and an undesired second position;
(b) fixing the indicator tab in a circumferential position such that the rotatable handle when disposed in the desired first position renders the indicator tab invisible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle, and such that the rotatable handle when disposed in the undesired second position renders the indicator tab visible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle; and
(c) viewing the valve assembly in a direction generally perpendicular to the plane of rotation of the valve handle to determine whether the indicator tab is visible or invisible, thereby determining whether the valve handle is in the desired first position or the undesired second position.
The first position of the rotatable handle may prohibit the flow of a fluid through the valve base and the undesired second position of the rotatable handle may allow the flow of a fluid through the valve base. Alternatively, the desired first position of the rotatable handle may allow the flow of a fluid through the valve base and the undesired second position of the rotatable handle may prohibit the flow of a fluid through the valve base.
The invention includes a fluid manifold system comprising
(a) a plurality of valve assemblies, each valve assembly comprising a valve base, a valve bonnet attached thereto, a rotatable valve stem extending coaxially through the valve bonnet, a rotatable valve handle attached to the valve stem and having a plane of rotation which is generally perpendicular to the axis of the valve stem, and an indicator tab attached to the valve base or the valve bonnet and extending outward from the valve base or the valve bonnet in a direction generally parallel to the plane of rotation of the valve handle, wherein the rotatable valve handle can be disposed in at least a first position and a second position, wherein the rotatable handle when disposed in the first position renders the indicator tab invisible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle, and wherein the rotatable handle when disposed in the second position renders the indicator tab visible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle; and
(b) manifold piping means which interconnect the valve assemblies such that flow of fluid through the valve assemblies and manifold can be controlled by setting the positions of the rotatable handles of the valve assemblies.
The positions of the rotatable handles on a portion of the valve assemblies may be located such that some of the indicator tabs are visible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle. The positions of the rotatable handles on a portion of the valve assemblies may be located such that at least some of the indicator tabs are visible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle. The positions of the rotatable handles on all of the valve assemblies may be set such that none of the indicator tabs are visible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle.
The invention includes a method of operating a fluid manifold system comprising
(a) providing a fluid manifold system which includes
(1) a plurality of valve assemblies, each valve assembly comprising a valve base, a valve bonnet attached thereto, a rotatable valve stem extending coaxially through the valve bonnet, a rotatable valve handle attached to the valve stem and having a plane of rotation which is generally perpendicular to the axis of the valve stem, and an indicator tab attached to the valve base or the valve bonnet and extending outward from the valve base or valve bonnet in a direction generally parallel to the plane of rotation of the valve handle, wherein the rotatable valve handle can be disposed in at least a first position and a second position, and
(2) manifold piping means which interconnect the valve assemblies such that flow of fluid through the valve assemblies and manifold can be controlled by setting the positions of the rotatable handles on the valve assemblies;
(b) locating the indicator tab on each valve assembly such that the rotatable handle on each valve assembly when disposed in either the first position or in the second position renders the indicator tab invisible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle;
(c) moving valve handles on the valve assemblies such that the indicator tabs on at least a portion of the valve assemblies are visible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle; and
(d) identifying the valve assemblies which have visible indicator tabs when viewed in a direction generally perpendicular to the plane of rotation of the valve handle and moving the valve handles on the valve assemblies so identified such that all indicator tabs on all valve assemblies are invisible when viewed in a direction generally perpendicular to the plane of rotation of the valve handle.